Britain used to be dominated by something called the two-party system – the Conservatives and Labour. When one gained, the other lost. Not any more. After the European elections of 2009 Britain has entered a new political world. Welcome to the Britain of eight-party politics.

Eight British parties will be sending MEPs to Brussels and Strasbourg for the next five years, a new record. A combination of the proportional representation system and the gradual desertion of the two major parties by the voters – only 43.4% of whom voted for the Tories and Labour in these elections – has redrawn the political map.

The Conservatives can claim victory in these elections. They got 1.7m more votes than their nearest challengers and will have 25 MEPs, 12 more than any other UK party. They came top of the poll in every region save Scotland, where they were beaten by the nationalists and Labour, and north-east England, where Labour held on. Yet with just 27.7% of the vote, more than seven points down on their estimated 35% national share in last week's local elections, these results underline that the Tory vote is not as solid as David Cameron must want it to be.

For Labour, the results are unequivocally cataclysmic. Third place, with only 2.4m votes and a poll share of 15.7%, is a record-breaking bad performance. Labour has never done as badly in a UK-wide election since the first world war. Only one in four Labour voters in the 2005 general election voted Labour last week. Labour lost Scotland and Wales, its old heartlands, in UK-wide elections for the first time in decades. Not surprisingly, Gordon Brown's position is again under threat.

The Liberal Democrats slipped a little in votes but gained another MEP – in the East Midlands. This is small consolation for Nick Clegg. In a contest seemingly tailor-made for the third party to profit from disaffection with the two major parties, the voters went to the margins, not to the Lib Dems.

The big winner was the UK Independence party. In the end, neither leadership squabbles nor expenses scandals could prevent the anti-EU party from repeating its 2004 success. Nearly 2.5 million voters chose Ukip, sending 13 MEPs to Brussels. Labour's collapse meant Ukip finished second in the popular vote for the first time.

The other winning parties were the Greens, who held their two seats, the far-right British National party, which won two seats and 6.2% of the national vote (though only 1.3% up on 2004), and the Scottish and Welsh nationalists. The biggest winners among these parties were the SNP, who thumped Labour into second place in Scotland.

Translating the European results into general election projections is a hazardous business. Nevertheless, anything close to Thursday's performance would produce a comfortable Conservative win and decimate Labour's ranks at Westminster. It would by some distance be Labour's worst general election ­performance in history.